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Everything posted by Nettron

  1. If we are talking line voltages there are commercially available handheld non-contact live wire detectors you can buy cheaply, i use them often on the job. http://www.industrialnewsroom.com/fullstory/22783
  2. I use Irfanview, it can convert a great many file types. I mainly use its screen capture feature on the options tab, with it i can copy, save to a file and convert a screen image in just one click. http://www.irfanview.com/
  3. Too bad thay dont have English built-in too ;D, kidding!
  4. Ooops, meant to say non-volitile EEPROM's.
  5. I assume by "microprocessor" we mean a microcontroller, yes ive seen that suggested on other forums. A controller such as the PIC can simulate in software just about any logic circuit. I agree this would be a good option if the IC count and "wiring" become too great, but like MP mentioned thats assuming one is comfortable with programming. This has somewhat jogged my memory ( excuse the coming pun) ,managed to dig up an old schemy of a circuit i once used for proramming SRAM memory IC's. Its an option to using a micro and for programming eliterates, its programmed one bit at a time via a non-encoded keypad. http://www.geocities.com/nettron1000/2816SRAM.html Only drawback is that the info will be lost when power is disconnected. A way around this problem would be to use EEPROM's.
  6. I mean the pendulum concept not the type of IC's used, although cmos would be better when it comes to power consumption, especially if we're talking portability. Taking a backseat at the moment i guess, im sure it can be refined, perhaps use a sinewave oscillator to drive a 3914('s). Making it more analog rather than digital would be something i would be even more interested in. ..and for todays special, 2 bags of LEDs for the price of 1 ;D yeah i can imagine a salesman's delight at someone designing a commercial circuit/kit with that many LEDs. Just more eye candy not really necessary .
  7. Appearently not all that original . http://www.eki.com/product.asp?number=2009 Maybe add a few more rows of LEDs, with different numbers of LEDs in each row, to simulate the "string" with the longest row representing the bobbin at the end. Maybe this belongs in another thread ? Appears do-able. Another option could be to build a circuit based on the internal window comparator on the 555 timer IC but with independent control over the charge/discharge rate and window reference voltages ( Vtrip upper/Vtrip lower).
  8. Remember i didnt have a LM3914 and was using LM339 comparator IC's. The idea i had in mind to solve the non-linearity problem, without adding another IC , was two-fold: 1. use different amounts of feedback around each comparators to "pull" the input voltage over threshold at appropriate timing intervals, 2. use a different reference voltage for each comparator. Yeah i know, it sounds ugly but that was 2 years ago and i havent looked at it since. Hmm...interesting,hadnt thought of that. AG maybe you should post a design based on that idea,I for one would really like to see something original.
  9. Yes i was looking at that earlier, nice little compact design. Its also available from Doctronics in kit form here: http://www.doctronics.co.uk/kits.htm#chaser Unfortunately wasnt enough LEDs for my app. Yep had looked into that as well, was thinking about taking the ramping voltage right off the timing capacitor on a 555 astable and use the LM3914 in dot mode. only problem was i didnt have a 3914 handy so tried the nuts-n-bolts route using comparators (LM339), had lots of those. But the design became too complex and just plain overkill, so later dropped the idea (violated the KISS rule). But something worth looking into.
  10. Audioguru, you have a point there, i was thinking the same thing when i was first designing the thing. Wish the 74154 had had some type of F-F and up/dn counter built-in. I had thought about using a 4017 but it would only give me sequencing in one direction with 10 LEDs. Do you know of a stand alone IC that can do dual sequencing of 16 LEDs or more ? Sorry MP, no i dont. I gave the board to my bro, seams he used it in a holloween costume for light effects. But I have the ExpressPC board layout on a floppy somewhere, i'll post it here if and when i find it.
  11. Heres a schematic of my up-down sequencial LED flasher that can sequence 16 LEDs, not sure how many LEDs were used in the original knightrider car . http://onfinite.three10.com/libraries/display.php?lid=8114&d=c524448053f994bcb48126b1b3904945
  12. Desmond, i see what you mean but im assumimg you will not be using the tester on an IC that has power connected to it ? To better explain what i mean with the sequencing scheme would require a schematic. Not sure what kind of results it will give you i havent breadboarded it yet but looks feasable. I can draw up and post a schematic a day or so if you dont mind the wait.
  13. MP, your missing the point, it doesnt matter what type of IC is being tested....but anyway, to overcome the problem with the 4066 or any other type of analog switch, you could use a sequencing scheme to multiplex the LEDs one by one. If two pins are "shorted" two LEDs will come on (light up).
  14. MP, im aware of what is meant by pins being shorted together, what im getting at is that internally IC pins generally do not short together, a short occurs from input to power supply ground or Vcc, depending on polarity. If by "shorted together" the OP is referring to bad soldering between pins then the LED scheme would suffice. Obviously when an LED is connected across two pins ( parallel) that have bin soldered together and power is supplied to the LED it will not light up.
  15. The OP's question appears unclear to me, when a pin on an IC go's short, it will do so to ground ( or supply )not between neighbouring pins. Am i misinterpreting this ?
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